New research highlights the potential for time-restricted eating and calorie timing as effective, sustainable alternatives for weight management and improving blood sugar levels.

To work: Meal Timing and Anthropometric and Metabolic Results. Image Credit: Pormezz / Shutterstock.com

In a recently published study JAMA Network Openresearchers conducted a systematic review and meta-analysis of randomized clinical trials (RCTs) to investigate the impact of meal timing strategies on body weight management and metabolic outcomes.

The effectiveness of modern approaches to weight loss

The global prevalence of obesity and overweight is rising sharply, in part due to modifiable lifestyle risk factors such as unhealthy dietary patterns and physical inactivity; both of these are associated with an increased risk of diabetes, cardiovascular disease, cancer and premature death.

Current estimates suggest that most individuals consume food and snack late at night for more than 14 hours each day, further increasing the risk of type 2 diabetes and worsening glycemic control. Comparatively, intermittent fasting, which involves consuming food during the active phase of the day for a period of six to ten hours, has emerged as a popular weight loss strategy.

Diet modification, including calorie restriction, is considered the primary strategy for body weight management. Meal timing strategies such as time-restricted eating (TRE), a type of intermittent fasting, reducing meal frequency, and varying calorie distribution throughout the day, have emerged as promising alternatives for people who find it difficult to monitor their daily calorie intake. weight loss.

In the current systematic review and meta-analysis, scientists analyze published RCTs to evaluate the long-term impact of meal timing strategies on anthropometric and metabolic outcomes in adults with and without metabolic disease.

Study design

The scientists searched several electronic databases to identify RCTs that investigated diurnal meal timing patterns for at least 12 weeks and reported anthropometric outcomes such as body weight and body mass index (BMI).

The final analysis included 29 RCTs involving 2,485 participants. Risk of bias analysis showed that approximately 76% of the selected studies provided low quality data.

Meal timing strategies evaluated in the RCTs reviewed; It included time-restricted eating, meal frequency, and daily calorie distribution.

time-restricted eating

A meta-analysis of RCTs investigating the effect of time-restricted eating on weight management found that this strategy can significantly reduce both body weight and BMI. However, time-restricted eating did not appear to affect lean body mass or waist circumference.

Study participants with a high BMI at baseline lost more weight than those with a low BMI. Greater weight loss was observed in those who consumed eight hours or less of food each day, compared to those who consumed more than eight hours of food each day.

Regarding metabolic outcomes, time-restricted eating was associated with reductions in fasting blood glucose, glycated hemoglobin (HbA1c), low-density lipoprotein (LDL) levels, and energy intake.

meal frequency

Lower meal frequency was associated with small reductions in body weight and BMI; However, meal frequency did not appear to affect lean mass or waist circumference measurements. Similarly, meal frequency did not appear to affect fasting glucose, HbA1c, LDL levels, or energy intake.

Calorie distribution

Consuming most calories early in the day leads to greater weight loss, lower BMI values, and reduced waist circumference measurements compared to consuming calories later in the day. Like meal frequency, no clear relationship was observed between calorie allocation and metabolic outcomes.

Operating limitations

A subgroup analysis of the current study confirmed that the weight-reducing effect of meal timing strategies was durable and did not depend on the training level of clinicians implementing the interventions. However, most of the clinical studies reviewed recruited participants from clinical settings and involved clinicians with nutrition training; This may limit the generalizability of the findings. Similarly, all clinical studies on calorie distribution included only female participants.

Another limitation of the current study is the low quality of evidence due to the risk of bias and inconsistency. Therefore, additional clinical studies with larger sample sizes, similar intervention designs, and longer follow-up periods should be conducted to provide more definitive conclusions about the health benefits of time-restricted eating.

Results

Meal timing strategies applied for more than 12 weeks can moderately reduce body weight, BMI, and waist circumference measurements. Time-restricted eating has also been found to reduce HbA1c and fasting glucose levels, thus indicating the potential benefit of this strategy for diabetes management.

The rigid nature of calorie counting in traditional weight loss interventions is one of the key reasons contributing to poor adherence, along with its association with higher disinhibition, energy intake and BMI. Comparatively, time-restricted eating may provide healthcare clinicians with a simpler and more flexible approach to support behavior change in overweight or obese adults.